It's very unlikely Bryan Singer will want to call attention to the Last Stand.He will be wanting to get on with the Days of future past story and not make reference to film
that at best had a mixed reaction.Now will he want to use a controvulated way to make the last Stand key to time travel plot.I seriously doudt any reference to the cure or
about Xavier's mind In other body.Some may not know this but In comics Xavier's mind has been In cloned body since the early 1980's.

Yes, he has been in a cloned body in the comics, and in an early story his place was taken by a shapeshifter called the Changeling (who could also imitate powers, unlike Mystique) who was killed. The team believed Xavier dead but he had gone into hiding to prepare for an alien invasion.

Nonetheless, a braindead twin does seem a bit of a stretch somehow.

I just hope they get on and announce the casting, so we can stop all this speculation.

If they include Xavier acting as though nothing happened, and Rogue with her powers back, then so be it. Let's just get on with it, because I'm tired of talking about it.